1. Field of the Invention
The present invention relates to a composition containing a pancreatic islet, a cell structure containing a pancreatic islet or a pancreatic islet cell, a pancreatic islet transplantation kit, a pancreatic islet cell transplantation treatment agent, and a hypoglycemic agent. The present invention further relates to a composition containing a pancreatic islet, a kit containing a pancreatic islet, a pancreatic islet transplantation treatment agent, and a hypoglycemic agent.
2. Description of the Related Art
Currently, regenerative medicine, which regenerates living body tissues and organs having functional disorders or dysfunction, is put into practical use. The regenerative medicine is new medical technology creating a form or a function of a living body tissue that cannot be recovered with only natural healing ability possessed by a living body, which is the same as that of an original tissue, again, using three factors including a cell, a scaffold, and a growth factor. In recent years, treatment using cells is gradually realized. Examples thereof include cartilage treatment using autologous chondrocytes, and cultured epidermis using autologous cells; bone regeneration treatment using mesenchymal stem cells; myocardial cell sheet treatment using myoblasts; cornea regeneration treatment using corneal epithelial sheets; and nerve regeneration treatment.
A cell structure, which contains cells and macromolecular blocks having biocompatibility, and in which the plurality of the above-described macromolecular blocks are arranged in gaps between the plurality of the above-described cells, is disclosed in WO2011/108517A. In the cell structure disclosed in WO2011/108517A, it is possible to deliver nutrients to the inside of the cell structure from the outside. The cell structure has a sufficient thickness, and cells exist in the structure uniformly. In Example of WO2011/108517A, high cell survival activity is verified using a macromolecular block formed of a recombinant gelatin material or a natural gelatin material. A cell structure for cell transplantation, which contains a macromolecular block having biocompatibility and at least one kind of cell, and in which the plurality of the above-described macromolecular blocks are arranged in the gaps between the plurality of the above-described cells, is disclosed in JP2014-12114A. In Example of JP2014-12114A, angiogenesis is evaluated using the cell structure for cell transplantation.
It is necessary for severe diabetic patients among diabetic patients to receive an insulin injection throughout their life. A transplantation treatment of transplanting a pancreatic islet which produces insulin into the liver of a diabetic patient to permanently fix the pancreatic islet to the liver is performed as a treatment method for releasing diabetic patients from an insulin injection. It is considered that there are β cells, which secrete insulin, in the pancreatic islet in the pancreas, and therefore, it is possible to secrete insulin by transplanting the pancreatic islet.
Transplantation treatment called pancreatic islet transplantation is performed on a patient whose pancreas cannot secrete insulin itself. It is considered that there are β cells, which secrete insulin, in the pancreatic islet in the pancreas, and therefore, it is possible to secrete insulin by transplanting the pancreatic islet. Currently, pancreatic islet transplantation using the Edmonton Protocol method in which a pancreatic islet is injected into blood from the portal vein is performed as the method for transplanting a pancreatic islet.
It is shown in Yanai G et al. (2013) Electrofusion of Mesenchymal Stem Cells and Islet Cells for Diabetes Therapy: A Rat Model. PLOS ONE, Volume 8, Issue 5, e64499 that glucose sensitivity disappears after 10 days of culturing in a case of using only a pancreatic islet in an in vitro glucose sensitivity test, but glucose sensitivity is maintained even after 10 days of culturing in a case of using pancreatic islet cells and mesenchymal stem cells which have been dispersed and in a case of using a fused body of pancreatic islet cells and mesenchymal stem cells (page 5, right column, lines 4 to 6, FIG. 5-b). In addition, in Yanai G et al. (2013) Electrofusion of Mesenchymal Stem Cells and Islet Cells for Diabetes Therapy: A Rat Model. PLOS ONE, Volume 8, Issue 5, e64499, the blood sugar level in vivo in a case of using only a pancreatic islet (Group 3) is the same as that in a case where a pancreatic islet and a mesenchymal stem cell is cultured together (Group 6) (FIG. 8a). It is shown in Ito T et al. (2010) Mesenchymal stem Cell and Islet Co-Transplantation Promotes Graft Revascularization and Function. Transplantation, Volume 89, Number 12, 1438-1445 that the blood sugar level is decreased by a transplanting mesenchymal stem cell and a pancreatic islet together whereas the blood sugar level is not decreased in a case where only a pancreatic islet is transplanted in vivo.